EFFECTS OF LOWER ALCOHOLS ON PARAMECIUM. 



259 



The Influence of Temperature on the Susceptibility of Para- 

 mecium to Ethyl Alcohol. Within reasonable limits of constancy 

 a given concentration of a given alcohol will narcotize a definite 

 per cent, of the organisms in a particular culture in one hour. 

 This fact makes it possible to compare quantitatively the narcotic 

 action of various alcohols, and to study the modifying influence 

 of physical conditions on the effects of a particular alcohol. 

 The method devised for counting the paramecia "' narcotized " 

 and those " unaffected r is elsewhere described (Bills, 1923^) . 



In the present experiment counts were made at widely different 

 temperatures 8 and 25. Paraincciuin caudatum, Clone 10, 

 and 3.0 per cent, ethyl alcohol were used, and all observations 

 made in duplicate. From the data presented in Table IV. it ap- 

 pears that the per cent, of the paramecia narcotized at 8 does 

 not differ significantly from the per cent, at 25. It seems 

 improbable (though of course possible) that intermediate tem- 

 peratures would show any markedly different values. 



TABLE IV. 



SHOWING THE INFLUENCE OF TEMPERATURE ON THE SUSCEPTIBILITY OF 



PARAMECIA TO ETHYL ALCOHOL. 

 The experiments were conducted in darkness. 



Average per cent, narcotized at 8 = 7.1. 

 Average per cent, narcotized at 25 = 7.9. 



The Influence of Light on the Susceptibility of Paramecium 

 to Ethyl Alcohol. Pairs of burettes containing paramecia of 

 Clone 10, with and without 3.0 per cent, ethyl alcohol were kept 

 for one hour in strong, but diffuse, northern, daylight, or in 

 direct, brilliant, sunlight in the middle of April. The direct 

 light passed obliquely through the thin glass walls of the burettes. 

 In all experiments the temperature was between 21 and 23. 



The data are presented in Table V. This table shows that di- 

 rect sunlight inactivated in one hour 28 per cent, of the organ- 



